https://github.com/krawaller/callbag-with-previous

https://github.com/krawaller/callbag-with-previous

Last synced: 18 days ago
JSON representation

• Host: GitHub
• URL: https://github.com/krawaller/callbag-with-previous
• Owner: krawaller
• License: mit
• Created: 2018-02-15T14:24:56.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-07-23T07:50:35.000Z (over 6 years ago)
• Last Synced: 2024-09-18T08:13:41.010Z (about 2 months ago)
• Language: JavaScript
• Size: 8.79 KB
• Stars: 3
• Watchers: 3
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: readme.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-callbags - with-previous

README

        
# callbag-with-previous

[Callbag](https://github.com/callbag/callbag) operator that puts the previous value alongside the current in an array.

```

[currentValue, previousValue]

```

The first output will also have `true` as a third item, to allow you to distinguish from the previous item being `undefined` and the first value.

```

[firstValue, undefined, true]

```

`npm install callbag-with-previous`

## example

```js

const fromIter = require('callbag-from-iter');

const forEach = require('callbag-for-each');

const withPrevious = require('callbag-with-previous');

const source = withPrevious(fromIter([1,2,3]));

forEach(x => console.log(x))(source); // [1, undefined, true]

                                      // [2, 1]

                                      // [3, 2]

```